The present invention relates to a novel method for blocking the maturation and production of microfilariae in an adult female filarial nematode comprising inhibiting the transglutaminase activity in the nematode by treatment with a transglutaminase inhibitor. Moreover, this invention has not only in vitro application but in vivo application for preventing the development of mature microfilariae of Brugia malayi and other filarial nematodes in a mammalian host by administration of a pharmacologically acceptable concentration of a transglutaminase inhibitor, monodansyl cadaverine, to the host. At higher concentrations the same transglutaminase inhibitor is filariacidal. Thus, transglutaminase inhibitors, especially monodansyl cadaverine, may play an important role in treating filariasis and thus helping to prevent the spread of these parasitic diseases.
Filariasis is a group of disorders produced by infection with threadlike nematodes of the superfamily Filarioidea. These nematodes invade the lymphatics and subcutaneous and deep tissues of the host, even causing blindness. The viviparous female discharges microfilariae into the blood or subcutaneous tissues where they live for weeks or months until they are taken up by hematophagous arthropods. Within these arthropod vectors the microfilariae metamorphose into the infective third-stage larvae (L.sub.3) in a period of several weeks. The L.sub.3 larvae migrate to the mouthparts of the arthropod vector and infect a new host when the arthropod takes another blood meal. The L.sub.3 larvae mature into adult nematodes over a period of several months and the fertilized females begin producing microfilariae, thus completing the cycle (1).
Nearly four hundred million people worldwide suffer from chronic infections caused by filarial nematodes (2). Filariasis is a major cause of morbidity in endemic areas of Africa, Asia, the Middle East, Pacific Islands, Central and South America, Mexico and the West Indies. Some of the more common types of filariasis are: Lymphatic filariasis produced by Wuchereria bancrofti, Brugia malayi and Brugia timori which causes lymphatic blockade and elephantiasis; Loiasis produced by Loa loa, also known as African Eye Worm, characterized by transient subcutaneous (Calabar) swellings as the adult nematodes migrate under the skin, including the conjunctiva of the eye; and Onchocerciasis or River Blindness, produced by Onchocerca volvulus, a cutaneous filariasis causing pruritic skin rash, sclerosing lymphadenitis, subcutaneous nodules and ocular lesions often leading to blindness (3,9). Gravid female nematodes can live as long as fifteen years within a host releasing thousands of microfilariae a day. The present chemotherapeutic treatments are unsatisfactory as most of them are inefficacious against the mature parasites while being microfilariacidal and frequently induce a severe allergic response to the death of the microfilariae known as the Mazzotti reaction. This allergic response can sometimes be fatal or in patients with Onchocerca volvulus may lead to the development of permanent eye lesions and blindness (4). Control of vectors has not proved to be sufficiently effective to interrupt transmission of the parasites.
An important discovery was made by the present inventors. They discovered that a pharmaceutically acceptable transglutaminase inhibitor, for example, monodansyl cadaverine, could prevent the formation of fully developed microfilariae in utero in adult female filarial nematodes by inhibiting a particular transglutaminase found in these female nematodes. Thus monodansyl cadaverine, administered parenterally, or possibly enterally, offers a means of treatment of filariasis in humans while avoiding the side effects of toxicity or allergic response to drug therapy. A discussion of the methods and applications of the present invention can be found in the present disclosure.
Abbreviations used herein include:
L.sub.3 infective third-stage larvae PA0 MDC monodansyl cadaverine [N- (5-aminopentyl) -5-dimethylamino-1-naphthalenesulfonamide] PA0 DDC dimethyl-dansyl cadaverine PA0 ul microliter PA0 FCS fetal calf serum PA0 Mf microfilariae PA0 ml milliliter PA0 uM micromolar PA0 mM millimolar PA0 EDTA ethylenediamine tetraacetic acid PA0 EGTA ethylene glycol (2-aminoethyl ether) tetraacetic acid PA0 CHAPS 3- [(3-cholamidopropyl) dimethylammino]-1-propane sulfonate PA0 SDS sodium dodecylsulfate PA0 PAGE polyacrylamide gel electrophoresis PA0 CUB-7401 monoclonal antibody against guinea pig liver tissue transglutaminase PA0 FITC fluorescein isothiocyanate PA0 PBS phosphate buffered saline PA0 IgG immunoglobulin G PA0 UV ultraviolet light PA0 IP intraperitoneally PA0 Kg kilogram PA0 mg milligram PA0 IV intravenously PA0 CO.sub.2 carbon dioxide